<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h1>App</h1>
    <button id="btn"></button>
</body>
<script>
    document.getElementById('btn').onclick = function(){
        localStorage.setItem('pawd',5201314)
    }
</script>
</html>